This study explores expressed wishes and requests for euthanasia (i.e. administration of lethal drugs at the explicit request of the patient), and incidence of end-of-life decisions with possible life-shortening effects (ELDs) in advanced lung cancer patients in Flanders, Belgium. We performed a prospective, longitudinal, observational study of a consecutive sample of advanced lung cancer patients and selected those who died within 18 months of diagnosis. Immediately after death, the pulmonologist/oncologist and general practitioner (GP) of the patient filled in a questionnaire. Information was available for 105 out of 115 deaths. According to the specialist or GP, one in five patients had expressed a wish for euthanasia; and three in four of these had made an explicit and repeated request. One in two of these received euthanasia. Of the patients who had expressed a wish for euthanasia but had not made an explicit and repeated request, none received euthanasia. Patients with a palliative treatment goal at inclusion were more likely to receive euthanasia. Death was preceded by an ELD in 62.9% of patients. To conclude, advanced lung cancer patients who expressed a euthanasia wish were often determined. Euthanasia was performed significantly more among patients whose treatment goal after diagnosis was exclusively palliative.